1. Field of the Invention
The present invention relates to a method and apparatus for automatic change of operations in an air separation plant in increasing or decreasing the amounts of products.
2. Description of the Prior Art
Operations in an air separation plant have heretofore been performed manually, and also operations of changing the amounts of product oxygen and product nitrogen in follow-up of changes in comsumption thereof have been performed manually. The equipment scale of an air separation plant is large and the heat capacity and mass capacity thereof are also large. Accordingly, a long time period is required for the so-called operation change, namely the change of the operation state from one steady operation state to another steady operation state, and further, since product oxygen and product nitrogen are continuously fed to steps using these products even during the operation change, it is required that supply of products inferior in quality is not allowed even for a very short time period. Accordingly, it is difficult to economically perform changing of outputs of products in follow-up of the comsumption thereof according to manual procedures.